From d4c8e96ef73e3554640cdb8afa0bbd6a794e17cf Mon Sep 17 00:00:00 2001
From: Ufuk <ufukty@gmail.com>
Date: Sat, 12 Sep 2020 22:43:45 +0300
Subject: [PATCH] replace until apt-get loop with separate function

---
 openvpn-install.sh | 31 ++++++++++++++++++++++---------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/openvpn-install.sh b/openvpn-install.sh
index 414cb07..57224ae 100755
--- a/openvpn-install.sh
+++ b/openvpn-install.sh
@@ -3,6 +3,19 @@
 # Secure OpenVPN server installer for Debian, Ubuntu, CentOS, Amazon Linux 2, Fedora and Arch Linux
 # https://github.com/angristan/openvpn-install
 
+function apt_get_with_retry() {
+    attempts=0
+    until apt-get $@; do 
+        attempts=$((attempts + 1))
+        if [[ $attempts -gt 10 ]]; then
+            echo "apt-get is busy right now, please try again later"
+            exit 1
+        fi
+        echo "Failed to run apt-get, trying again..."
+        sleep 1
+    done
+}
+
 function isRoot() {
 	if [ "$EUID" -ne 0 ]; then
 		return 1
@@ -99,7 +112,7 @@ function installUnbound() {
 	if [[ ! -e /etc/unbound/unbound.conf ]]; then
 
 		if [[ $OS =~ (debian|ubuntu) ]]; then
-			until apt-get install -y unbound; do sleep 1; done
+			apt_get_with_retry install -y unbound
 			# Configuration
 			echo 'interface: 10.8.0.1
 access-control: 10.8.0.1/24 allow
@@ -226,7 +239,7 @@ function installQuestions() {
 	if [[ $APPROVE_IP =~ n ]]; then
 		read -rp "IP address: " -e -i "$IP" IP
 	fi
-	# If $IP is a private IP address, the server must be behind NAT
+	# If $IP is a private IP address, the server must be behind NAT
 	if echo "$IP" | grep -qE '^(10\.|172\.1[6789]\.|172\.2[0-9]\.|172\.3[01]\.|192\.168)'; then
 		echo ""
 		echo "It seems this server is behind NAT. What is its public IPv4 address or hostname?"
@@ -647,16 +660,16 @@ function installOpenVPN() {
 	# the first time.
 	if [[ ! -e /etc/openvpn/server.conf ]]; then
 		if [[ $OS =~ (debian|ubuntu) ]]; then
-			until apt-get update; do sleep 1; done
-			until apt-get -y install ca-certificates gnupg; do sleep 1; done
+			apt_get_with_retry update
+			apt_get_with_retry -y install ca-certificates gnupg
 			# We add the OpenVPN repo to get the latest version.
 			if [[ $VERSION_ID == "16.04" ]]; then
 				echo "deb http://build.openvpn.net/debian/openvpn/stable xenial main" >/etc/apt/sources.list.d/openvpn.list
 				wget -O - https://swupdate.openvpn.net/repos/repo-public.gpg | apt-key add -
-				until apt-get update; do sleep 1; done
+				apt_get_with_retry update
 			fi
 			# Ubuntu > 16.04 and Debian > 8 have OpenVPN >= 2.4 without the need of a third party repository.
-			until apt-get install -y openvpn iptables openssl wget ca-certificates curl; do sleep 1; done
+			apt_get_with_retry install -y openvpn iptables openssl wget ca-certificates curl
 		elif [[ $OS == 'centos' ]]; then
 			yum install -y epel-release
 			yum install -y openvpn iptables openssl wget ca-certificates curl tar 'policycoreutils-python*'
@@ -1181,7 +1194,7 @@ function removeUnbound() {
 		systemctl stop unbound
 
 		if [[ $OS =~ (debian|ubuntu) ]]; then
-			until apt-get autoremove --purge -y unbound; do sleep 1; done
+			apt_get_with_retry autoremove --purge -y unbound
 		elif [[ $OS == 'arch' ]]; then
 			pacman --noconfirm -R unbound
 		elif [[ $OS =~ (centos|amzn) ]]; then
@@ -1244,10 +1257,10 @@ function removeOpenVPN() {
 		fi
 
 		if [[ $OS =~ (debian|ubuntu) ]]; then
-			until apt-get autoremove --purge -y openvpn; do sleep 1; done
+			apt_get_with_retry autoremove --purge -y openvpn
 			if [[ -e /etc/apt/sources.list.d/openvpn.list ]]; then
 				rm /etc/apt/sources.list.d/openvpn.list
-				until apt-get update; do sleep 1; done
+				apt_get_with_retry update
 			fi
 		elif [[ $OS == 'arch' ]]; then
 			pacman --noconfirm -R openvpn